One of my uncles is a horse and another is a giant snake and another is a giant wolf so you know what, that's fair.

Relics can be a lot of different things. It's just something you channel your power through. It doesn't have to be ancient, and it's usually easier if they aren't so they're less suspicious. As far as most people are concerned, either no gods exist or just one all-powerful one. You can't exactly go around with a giant spear or something and say it's blessed by a god.